drivers/net/arcnet/rfc1201.c

   1 /*
   2  * Linux ARCnet driver - RFC1201 (standard) packet encapsulation
   3  *
   4  * Written 1994-1999 by Avery Pennarun.
   5  * Derived from skeleton.c by Donald Becker.
   6  *
   7  * Special thanks to Contemporary Controls, Inc. (www.ccontrols.com)
   8  *  for sponsoring the further development of this driver.
   9  *
  10  * **********************
  11  *
  12  * The original copyright of skeleton.c was as follows:
  13  *
  14  * skeleton.c Written 1993 by Donald Becker.
  15  * Copyright 1993 United States Government as represented by the
  16  * Director, National Security Agency.  This software may only be used
  17  * and distributed according to the terms of the GNU General Public License as
  18  * modified by SRC, incorporated herein by reference.
  19  *
  20  * **********************
  21  *
  22  * For more details, see drivers/net/arcnet.c
  23  *
  24  * **********************
  25  */
  26 #include <linux/gfp.h>
  27 #include <linux/module.h>
  28 #include <linux/init.h>
  29 #include <linux/if_arp.h>
  30 #include <linux/netdevice.h>
  31 #include <linux/skbuff.h>
  32 #include <linux/arcdevice.h>
  33
  34 MODULE_LICENSE("GPL");
  35 #define VERSION "arcnet: RFC1201 \"standard\" (`a') encapsulation support loaded.\n"
  36
  37 static __be16 type_trans(struct sk_buff *skb, struct net_device *dev);
  38 static void rx(struct net_device *dev, int bufnum,
  39                struct archdr *pkthdr, int length);
  40 static int build_header(struct sk_buff *skb, struct net_device *dev,
  41                         unsigned short type, uint8_t daddr);
  42 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
  43                       int bufnum);
  44 static int continue_tx(struct net_device *dev, int bufnum);
  45
  46 static struct ArcProto rfc1201_proto = {
  47         .suffix         = 'a',
  48         .mtu            = 1500, /* could be more, but some receivers can't handle it... */
  49         .is_ip          = 1,    /* This is for sending IP and ARP packages */
  50         .rx             = rx,
  51         .build_header   = build_header,
  52         .prepare_tx     = prepare_tx,
  53         .continue_tx    = continue_tx,
  54         .ack_tx         = NULL
  55 };
  56
  57 static int __init arcnet_rfc1201_init(void)
  58 {
  59         printk(VERSION);
  60
  61         arc_proto_map[ARC_P_IP]
  62             = arc_proto_map[ARC_P_IPV6]
  63             = arc_proto_map[ARC_P_ARP]
  64             = arc_proto_map[ARC_P_RARP]
  65             = arc_proto_map[ARC_P_IPX]
  66             = arc_proto_map[ARC_P_NOVELL_EC]
  67             = &rfc1201_proto;
  68
  69         /* if someone else already owns the broadcast, we won't take it */
  70         if (arc_bcast_proto == arc_proto_default)
  71                 arc_bcast_proto = &rfc1201_proto;
  72
  73         return 0;
  74 }
  75
  76 static void __exit arcnet_rfc1201_exit(void)
  77 {
  78         arcnet_unregister_proto(&rfc1201_proto);
  79 }
  80
  81 module_init(arcnet_rfc1201_init);
  82 module_exit(arcnet_rfc1201_exit);
  83
  84 /*
  85  * Determine a packet's protocol ID.
  86  *
  87  * With ARCnet we have to convert everything to Ethernet-style stuff.
  88  */
  89 static __be16 type_trans(struct sk_buff *skb, struct net_device *dev)
  90 {
  91         struct archdr *pkt = (struct archdr *)skb->data;
  92         struct arc_rfc1201 *soft = &pkt->soft.rfc1201;
  93         int hdr_size = ARC_HDR_SIZE + RFC1201_HDR_SIZE;
  94
  95         /* Pull off the arcnet header. */
  96         skb_reset_mac_header(skb);
  97         skb_pull(skb, hdr_size);
  98
  99         if (pkt->hard.dest == 0) {
 100                 skb->pkt_type = PACKET_BROADCAST;
 101         } else if (dev->flags & IFF_PROMISC) {
 102                 /* if we're not sending to ourselves :) */
 103                 if (pkt->hard.dest != dev->dev_addr[0])
 104                         skb->pkt_type = PACKET_OTHERHOST;
 105         }
 106         /* now return the protocol number */
 107         switch (soft->proto) {
 108         case ARC_P_IP:
 109                 return htons(ETH_P_IP);
 110         case ARC_P_IPV6:
 111                 return htons(ETH_P_IPV6);
 112         case ARC_P_ARP:
 113                 return htons(ETH_P_ARP);
 114         case ARC_P_RARP:
 115                 return htons(ETH_P_RARP);
 116
 117         case ARC_P_IPX:
 118         case ARC_P_NOVELL_EC:
 119                 return htons(ETH_P_802_3);
 120         default:
 121                 dev->stats.rx_errors++;
 122                 dev->stats.rx_crc_errors++;
 123                 return 0;
 124         }
 125
 126         return htons(ETH_P_IP);
 127 }
 128
 129 /* packet receiver */
 130 static void rx(struct net_device *dev, int bufnum,
 131                struct archdr *pkthdr, int length)
 132 {
 133         struct arcnet_local *lp = netdev_priv(dev);
 134         struct sk_buff *skb;
 135         struct archdr *pkt = pkthdr;
 136         struct arc_rfc1201 *soft = &pkthdr->soft.rfc1201;
 137         int saddr = pkt->hard.source, ofs;
 138         struct Incoming *in = &lp->rfc1201.incoming[saddr];
 139
 140         BUGMSG(D_DURING, "it's an RFC1201 packet (length=%d)\n", length);
 141
 142         if (length >= MinTU)
 143                 ofs = 512 - length;
 144         else
 145                 ofs = 256 - length;
 146
 147         if (soft->split_flag == 0xFF) {         /* Exception Packet */
 148                 if (length >= 4 + RFC1201_HDR_SIZE) {
 149                         BUGMSG(D_DURING, "compensating for exception packet\n");
 150                 } else {
 151                         BUGMSG(D_EXTRA, "short RFC1201 exception packet from %02Xh",
 152                                saddr);
 153                         return;
 154                 }
 155
 156                 /* skip over 4-byte junkola */
 157                 length -= 4;
 158                 ofs += 4;
 159                 lp->hw.copy_from_card(dev, bufnum, 512 - length,
 160                                       soft, sizeof(pkt->soft));
 161         }
 162         if (!soft->split_flag) {        /* not split */
 163                 BUGMSG(D_RX, "incoming is not split (splitflag=%d)\n",
 164                        soft->split_flag);
 165
 166                 if (in->skb) {  /* already assembling one! */
 167                         BUGMSG(D_EXTRA, "aborting assembly (seq=%d) for unsplit packet (splitflag=%d, seq=%d)\n",
 168                                in->sequence, soft->split_flag, soft->sequence);
 169                         lp->rfc1201.aborted_seq = soft->sequence;
 170                         dev_kfree_skb_irq(in->skb);
 171                         dev->stats.rx_errors++;
 172                         dev->stats.rx_missed_errors++;
 173                         in->skb = NULL;
 174                 }
 175                 in->sequence = soft->sequence;
 176
 177                 skb = alloc_skb(length + ARC_HDR_SIZE, GFP_ATOMIC);
 178                 if (skb == NULL) {
 179                         BUGMSG(D_NORMAL, "Memory squeeze, dropping packet.\n");
 180                         dev->stats.rx_dropped++;
 181                         return;
 182                 }
 183                 skb_put(skb, length + ARC_HDR_SIZE);
 184                 skb->dev = dev;
 185
 186                 pkt = (struct archdr *)skb->data;
 187                 soft = &pkt->soft.rfc1201;
 188
 189                 /* up to sizeof(pkt->soft) has already been copied from the card */
 190                 memcpy(pkt, pkthdr, sizeof(struct archdr));
 191                 if (length > sizeof(pkt->soft))
 192                         lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft),
 193                                        pkt->soft.raw + sizeof(pkt->soft),
 194                                               length - sizeof(pkt->soft));
 195
 196                 /*
 197                  * ARP packets have problems when sent from some DOS systems: the
 198                  * source address is always 0!  So we take the hardware source addr
 199                  * (which is impossible to fumble) and insert it ourselves.
 200                  */
 201                 if (soft->proto == ARC_P_ARP) {
 202                         struct arphdr *arp = (struct arphdr *)soft->payload;
 203
 204                         /* make sure addresses are the right length */
 205                         if (arp->ar_hln == 1 && arp->ar_pln == 4) {
 206                                 uint8_t *cptr = (uint8_t *)arp + sizeof(struct arphdr);
 207
 208                                 if (!*cptr) {   /* is saddr = 00? */
 209                                         BUGMSG(D_EXTRA,
 210                                                "ARP source address was 00h, set to %02Xh.\n",
 211                                                saddr);
 212                                         dev->stats.rx_crc_errors++;
 213                                         *cptr = saddr;
 214                                 } else {
 215                                         BUGMSG(D_DURING, "ARP source address (%Xh) is fine.\n",
 216                                                *cptr);
 217                                 }
 218                         } else {
 219                                 BUGMSG(D_NORMAL, "funny-shaped ARP packet. (%Xh, %Xh)\n",
 220                                        arp->ar_hln, arp->ar_pln);
 221                                 dev->stats.rx_errors++;
 222                                 dev->stats.rx_crc_errors++;
 223                         }
 224                 }
 225                 BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx");
 226
 227                 skb->protocol = type_trans(skb, dev);
 228                 netif_rx(skb);
 229         } else {                /* split packet */
 230                 /*
 231                  * NOTE: MSDOS ARP packet correction should only need to apply to
 232                  * unsplit packets, since ARP packets are so short.
 233                  *
 234                  * My interpretation of the RFC1201 document is that if a packet is
 235                  * received out of order, the entire assembly process should be
 236                  * aborted.
 237                  *
 238                  * The RFC also mentions "it is possible for successfully received
 239                  * packets to be retransmitted." As of 0.40 all previously received
 240                  * packets are allowed, not just the most recent one.
 241                  *
 242                  * We allow multiple assembly processes, one for each ARCnet card
 243                  * possible on the network.  Seems rather like a waste of memory,
 244                  * but there's no other way to be reliable.
 245                  */
 246
 247                 BUGMSG(D_RX, "packet is split (splitflag=%d, seq=%d)\n",
 248                        soft->split_flag, in->sequence);
 249
 250                 if (in->skb && in->sequence != soft->sequence) {
 251                         BUGMSG(D_EXTRA, "wrong seq number (saddr=%d, expected=%d, seq=%d, splitflag=%d)\n",
 252                                saddr, in->sequence, soft->sequence,
 253                                soft->split_flag);
 254                         dev_kfree_skb_irq(in->skb);
 255                         in->skb = NULL;
 256                         dev->stats.rx_errors++;
 257                         dev->stats.rx_missed_errors++;
 258                         in->lastpacket = in->numpackets = 0;
 259                 }
 260                 if (soft->split_flag & 1) {     /* first packet in split */
 261                         BUGMSG(D_RX, "brand new splitpacket (splitflag=%d)\n",
 262                                soft->split_flag);
 263                         if (in->skb) {  /* already assembling one! */
 264                                 BUGMSG(D_EXTRA, "aborting previous (seq=%d) assembly (splitflag=%d, seq=%d)\n",
 265                                        in->sequence, soft->split_flag,
 266                                        soft->sequence);
 267                                 dev->stats.rx_errors++;
 268                                 dev->stats.rx_missed_errors++;
 269                                 dev_kfree_skb_irq(in->skb);
 270                         }
 271                         in->sequence = soft->sequence;
 272                         in->numpackets = ((unsigned)soft->split_flag >> 1) + 2;
 273                         in->lastpacket = 1;
 274
 275                         if (in->numpackets > 16) {
 276                                 BUGMSG(D_EXTRA, "incoming packet more than 16 segments; dropping. (splitflag=%d)\n",
 277                                        soft->split_flag);
 278                                 lp->rfc1201.aborted_seq = soft->sequence;
 279                                 dev->stats.rx_errors++;
 280                                 dev->stats.rx_length_errors++;
 281                                 return;
 282                         }
 283                         in->skb = skb = alloc_skb(508 * in->numpackets + ARC_HDR_SIZE,
 284                                                   GFP_ATOMIC);
 285                         if (skb == NULL) {
 286                                 BUGMSG(D_NORMAL, "(split) memory squeeze, dropping packet.\n");
 287                                 lp->rfc1201.aborted_seq = soft->sequence;
 288                                 dev->stats.rx_dropped++;
 289                                 return;
 290                         }
 291                         skb->dev = dev;
 292                         pkt = (struct archdr *)skb->data;
 293                         soft = &pkt->soft.rfc1201;
 294
 295                         memcpy(pkt, pkthdr, ARC_HDR_SIZE + RFC1201_HDR_SIZE);
 296                         skb_put(skb, ARC_HDR_SIZE + RFC1201_HDR_SIZE);
 297
 298                         soft->split_flag = 0;   /* end result won't be split */
 299                 } else {        /* not first packet */
 300                         int packetnum = ((unsigned)soft->split_flag >> 1) + 1;
 301
 302                         /*
 303                          * if we're not assembling, there's no point trying to
 304                          * continue.
 305                          */
 306                         if (!in->skb) {
 307                                 if (lp->rfc1201.aborted_seq != soft->sequence) {
 308                                         BUGMSG(D_EXTRA, "can't continue split without starting first! (splitflag=%d, seq=%d, aborted=%d)\n",
 309                                         soft->split_flag, soft->sequence,
 310                                                lp->rfc1201.aborted_seq);
 311                                         dev->stats.rx_errors++;
 312                                         dev->stats.rx_missed_errors++;
 313                                 }
 314                                 return;
 315                         }
 316                         in->lastpacket++;
 317                         if (packetnum != in->lastpacket) {      /* not the right flag! */
 318                                 /* harmless duplicate? ignore. */
 319                                 if (packetnum <= in->lastpacket - 1) {
 320                                         BUGMSG(D_EXTRA, "duplicate splitpacket ignored! (splitflag=%d)\n",
 321                                                soft->split_flag);
 322                                         dev->stats.rx_errors++;
 323                                         dev->stats.rx_frame_errors++;
 324                                         return;
 325                                 }
 326                                 /* "bad" duplicate, kill reassembly */
 327                                 BUGMSG(D_EXTRA, "out-of-order splitpacket, reassembly (seq=%d) aborted (splitflag=%d, seq=%d)\n",
 328                                        in->sequence, soft->split_flag, soft->sequence);
 329                                 lp->rfc1201.aborted_seq = soft->sequence;
 330                                 dev_kfree_skb_irq(in->skb);
 331                                 in->skb = NULL;
 332                                 dev->stats.rx_errors++;
 333                                 dev->stats.rx_missed_errors++;
 334                                 in->lastpacket = in->numpackets = 0;
 335                                 return;
 336                         }
 337                         pkt = (struct archdr *)in->skb->data;
 338                         soft = &pkt->soft.rfc1201;
 339                 }
 340
 341                 skb = in->skb;
 342
 343                 lp->hw.copy_from_card(dev, bufnum, ofs + RFC1201_HDR_SIZE,
 344                                       skb->data + skb->len,
 345                                       length - RFC1201_HDR_SIZE);
 346                 skb_put(skb, length - RFC1201_HDR_SIZE);
 347
 348                 /* are we done? */
 349                 if (in->lastpacket == in->numpackets) {
 350                         in->skb = NULL;
 351                         in->lastpacket = in->numpackets = 0;
 352
 353                         BUGMSG(D_SKB_SIZE, "skb: received %d bytes from %02X (unsplit)\n",
 354                                skb->len, pkt->hard.source);
 355                         BUGMSG(D_SKB_SIZE, "skb: received %d bytes from %02X (split)\n",
 356                                skb->len, pkt->hard.source);
 357                         BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx");
 358
 359                         skb->protocol = type_trans(skb, dev);
 360                         netif_rx(skb);
 361                 }
 362         }
 363 }
 364
 365 /* Create the ARCnet hard/soft headers for RFC1201. */
 366 static int build_header(struct sk_buff *skb, struct net_device *dev,
 367                         unsigned short type, uint8_t daddr)
 368 {
 369         struct arcnet_local *lp = netdev_priv(dev);
 370         int hdr_size = ARC_HDR_SIZE + RFC1201_HDR_SIZE;
 371         struct archdr *pkt = (struct archdr *)skb_push(skb, hdr_size);
 372         struct arc_rfc1201 *soft = &pkt->soft.rfc1201;
 373
 374         /* set the protocol ID according to RFC1201 */
 375         switch (type) {
 376         case ETH_P_IP:
 377                 soft->proto = ARC_P_IP;
 378                 break;
 379         case ETH_P_IPV6:
 380                 soft->proto = ARC_P_IPV6;
 381                 break;
 382         case ETH_P_ARP:
 383                 soft->proto = ARC_P_ARP;
 384                 break;
 385         case ETH_P_RARP:
 386                 soft->proto = ARC_P_RARP;
 387                 break;
 388         case ETH_P_IPX:
 389         case ETH_P_802_3:
 390         case ETH_P_802_2:
 391                 soft->proto = ARC_P_IPX;
 392                 break;
 393         case ETH_P_ATALK:
 394                 soft->proto = ARC_P_ATALK;
 395                 break;
 396         default:
 397                 BUGMSG(D_NORMAL, "RFC1201: I don't understand protocol %d (%Xh)\n",
 398                        type, type);
 399                 dev->stats.tx_errors++;
 400                 dev->stats.tx_aborted_errors++;
 401                 return 0;
 402         }
 403
 404         /*
 405          * Set the source hardware address.
 406          *
 407          * This is pretty pointless for most purposes, but it can help in
 408          * debugging.  ARCnet does not allow us to change the source address in
 409          * the actual packet sent)
 410          */
 411         pkt->hard.source = *dev->dev_addr;
 412
 413         soft->sequence = htons(lp->rfc1201.sequence++);
 414         soft->split_flag = 0;   /* split packets are done elsewhere */
 415
 416         /* see linux/net/ethernet/eth.c to see where I got the following */
 417
 418         if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
 419                 /*
 420                  * FIXME: fill in the last byte of the dest ipaddr here to better
 421                  * comply with RFC1051 in "noarp" mode.  For now, always broadcasting
 422                  * will probably at least get packets sent out :)
 423                  */
 424                 pkt->hard.dest = 0;
 425                 return hdr_size;
 426         }
 427         /* otherwise, drop in the dest address */
 428         pkt->hard.dest = daddr;
 429         return hdr_size;
 430 }
 431
 432 static void load_pkt(struct net_device *dev, struct arc_hardware *hard,
 433                      struct arc_rfc1201 *soft, int softlen, int bufnum)
 434 {
 435         struct arcnet_local *lp = netdev_priv(dev);
 436         int ofs;
 437
 438         /* assume length <= XMTU: someone should have handled that by now. */
 439
 440         if (softlen > MinTU) {
 441                 hard->offset[0] = 0;
 442                 hard->offset[1] = ofs = 512 - softlen;
 443         } else if (softlen > MTU) {     /* exception packet - add an extra header */
 444                 struct arc_rfc1201 excsoft;
 445
 446                 excsoft.proto = soft->proto;
 447                 excsoft.split_flag = 0xff;
 448                 excsoft.sequence = htons(0xffff);
 449
 450                 hard->offset[0] = 0;
 451                 ofs = 512 - softlen;
 452                 hard->offset[1] = ofs - RFC1201_HDR_SIZE;
 453                 lp->hw.copy_to_card(dev, bufnum, ofs - RFC1201_HDR_SIZE,
 454                                     &excsoft, RFC1201_HDR_SIZE);
 455         } else {
 456                 hard->offset[0] = ofs = 256 - softlen;
 457         }
 458
 459         lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE);
 460         lp->hw.copy_to_card(dev, bufnum, ofs, soft, softlen);
 461
 462         lp->lastload_dest = hard->dest;
 463 }
 464
 465 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
 466                       int bufnum)
 467 {
 468         struct arcnet_local *lp = netdev_priv(dev);
 469         const int maxsegsize = XMTU - RFC1201_HDR_SIZE;
 470         struct Outgoing *out;
 471
 472         BUGMSG(D_DURING, "prepare_tx: txbufs=%d/%d/%d\n",
 473                lp->next_tx, lp->cur_tx, bufnum);
 474
 475         length -= ARC_HDR_SIZE; /* hard header is not included in packet length */
 476         pkt->soft.rfc1201.split_flag = 0;
 477
 478         /* need to do a split packet? */
 479         if (length > XMTU) {
 480                 out = &lp->outgoing;
 481
 482                 out->length = length - RFC1201_HDR_SIZE;
 483                 out->dataleft = lp->outgoing.length;
 484                 out->numsegs = (out->dataleft + maxsegsize - 1) / maxsegsize;
 485                 out->segnum = 0;
 486
 487                 BUGMSG(D_DURING, "rfc1201 prep_tx: ready for %d-segment split (%d bytes, seq=%d)\n",
 488                        out->numsegs, out->length,
 489                        pkt->soft.rfc1201.sequence);
 490
 491                 return 0;       /* not done */
 492         }
 493         /* just load the packet into the buffers and send it off */
 494         load_pkt(dev, &pkt->hard, &pkt->soft.rfc1201, length, bufnum);
 495
 496         return 1;               /* done */
 497 }
 498
 499 static int continue_tx(struct net_device *dev, int bufnum)
 500 {
 501         struct arcnet_local *lp = netdev_priv(dev);
 502         struct Outgoing *out = &lp->outgoing;
 503         struct arc_hardware *hard = &out->pkt->hard;
 504         struct arc_rfc1201 *soft = &out->pkt->soft.rfc1201, *newsoft;
 505         int maxsegsize = XMTU - RFC1201_HDR_SIZE;
 506         int seglen;
 507
 508         BUGMSG(D_DURING,
 509                "rfc1201 continue_tx: loading segment %d(+1) of %d (seq=%d)\n",
 510                out->segnum, out->numsegs, soft->sequence);
 511
 512         /* the "new" soft header comes right before the data chunk */
 513         newsoft = (struct arc_rfc1201 *)
 514             (out->pkt->soft.raw + out->length - out->dataleft);
 515
 516         if (!out->segnum)       /* first packet; newsoft == soft */
 517                 newsoft->split_flag = ((out->numsegs - 2) << 1) | 1;
 518         else {
 519                 newsoft->split_flag = out->segnum << 1;
 520                 newsoft->proto = soft->proto;
 521                 newsoft->sequence = soft->sequence;
 522         }
 523
 524         seglen = maxsegsize;
 525         if (seglen > out->dataleft)
 526                 seglen = out->dataleft;
 527         out->dataleft -= seglen;
 528
 529         load_pkt(dev, hard, newsoft, seglen + RFC1201_HDR_SIZE, bufnum);
 530
 531         out->segnum++;
 532         if (out->segnum >= out->numsegs)
 533                 return 1;
 534         else
 535                 return 0;
 536 }